CHRONIC-FATIGUE SYNDROME, or CFS, which afflicts over 1m people in America and 250,000 in Britain, is certainly chronic and surely fatiguing. But is it truly a syndrome, a set of symptoms reliably associated together and thought to have a single underlying cause—in other words, a definable disease?
CFS’s symptoms—debilitating exhaustion often accompanied by pain, muscle weakness, sleep problems, “brain fog” and depression—overlap with those of other conditions. These include fibromyalgia (itself the subject of existential doubt), clinical depression, insomnia and other sleep disorders, anaemia and diabetes. These overlaps lead some to be sceptical about CFS’s syndromic nature. They also mean many people with CFS spend years on an expensive “diagnostic odyssey” to try to find out what is going on….